Changes in epiphyseal signal on MR imaging of the hip are well documented in established Perthes disease. We report an unusual case in which the initial MRI findings of isolated metaphyseal oedema without epiphyseal changes or hip effusion resulted in delayed diagnosis.
A 5 year old boy presented with a 7 day history of a limp and right hip pain. He was being treated with oral steroids for chronic renal failure. The initial hip radiograph was normal, and ultrasound excluded hip effusion. All inflammatory markers and his white cell count were within normal limits. An MR of his pelvis and hips was performed shortly after presentation. This demonstrated isolated metaphyseal oedema in the right femoral neck, a normal epiphysis, and confirmed the absence of a hip effusion (Figure 1). Osteonecrosis was thought to be unlikely on the basis of the initial MR. However, the child continued to complain of persistent hip pain, and six months later, his hip radiograph revealed the classical changes of advanced Perthe's disease (Figure 2).
Legg-Calve-Perthes disease is an idiopathic avascular necrosis of the femoral head seen in children. It has an age distribution of 2-12 years old with a peak incidence at 4-8 years of age. There is a male preponderance with a male-to-female ratio of approximately 5:1 and 5-10% of cases are bilateral. Pathological correlation suggests multiple episodes of major infarction leading to avascular necrosis of the epiphysis followed by revascularisation and healing. Early disease, as in our example, may not show any abnormality on plain film radiography. Ultrasound may demonstrate a joint effusion but this is not a consistent finding. MRI will detect the condition before findings are apparent on plain film and is therefore mandatory in patients with persistent symptoms. Changes in epiphyseal signal on MR imaging of the hip are well documented in established Perthes disease, and MR visualises epiphyseal involvement best 3-8 months after the first symptoms1. Isolated metaphyseal oedema has been reported previously . One study observed isolated metaphyseal oedema in 12 patients from a cohort of 65 cases of Perthes disease, suggesting an incidence of 18%.2. It is recognised as a indicator of poor outcome, predicting widespread epiphyseal necrosis within three months of the first symptoms1,. The metaphyseal changes remain poorly understood but some authors have postulated that disturbed venous drainage of the femoral neck in active Perthes disease results in venous hypertension3. The case reported here is an important reminder that there is spectrum of imaging findings in Perthes disease, and that isolated metaphyseal oedema may be indicative of a rapidly progressive form of the disease.
Legg-Calve-Perthes Disease
Based on the child’s age (5-year-old boy), clinical presentation (especially persistent discomfort or limping in the hip region), and imaging findings showing “proximal femoral metaphyseal edema without significant collapse or necrosis of the femoral head,” the most likely diagnosis is:
Considering the progression of avascular necrosis of the femoral head, if symptoms persist or worsen, repeated MRI and X-ray assessments are advised to monitor the extent and evolution of necrosis.
1. Treatment Strategy Overview
2. Rehabilitation/Exercise Prescription Recommendations
Throughout the rehabilitation process, training volume and methods should be individualized based on the child’s condition and follow-up imaging, to prevent secondary injuries from incorrect or excessive training.
This report provides a reference analysis based on the currently available imaging and medical history. It should not replace in-person medical consultations or professional advice. If any doubts or worsening symptoms occur, please consult a specialist for further evaluation or treatment.
Legg-Calve-Perthes Disease
